LAVAL, Quebec — Generic drug maker Actavis has filed for approval of a generic version of an antidepressant made by Canada’s Labopharm, Labopharm said.

The drug maker said it received a notification stating that Actavis had applied to the Food and Drug Administration for approval of a generic version of Oletpro (trazodone hydrochloride) extended-release tablets in the 150-mg and 300-mg strengths.

Actavis’ application contained a Paragraph IV certification, a legal challenge to a Labopharm patent covering the drug, which expires in June 2020. The market exclusivity period, which prevents the FDA from approving Actavis’ version, expires in February 2013.

Labopharm said it was reviewing the letter to determine what steps to take, though under the Hatch-Waxman Act of 1984, it is allowed to file a lawsuit against Actavis to prevent the latter from marketing its generic version of the drug.